Tension-responsive fastener drive system

ABSTRACT

A tension-responsive fastener drive system is disclosed in which tension arising in a fastener is sensed by a feeler gauge. The gauge applies a retardive force to a sensing sleeve mounted for motion with the fastener drive shaft. When fastener drive shaftsensing sleeve motion becomes unequal, or when the sensing sleeve is angularly displaced relative to the drive shaft, a stop mechanism is actuated to halt further fastener driving action. Thus, a predetermined tension can be applied to a fastener when the fastener is driven into or secured on a workpiece.

United States Patent 11 1 1111 3,906,819

Curtis Sept. 23, 1975 [5 TENSION-RESPONSIVE FASTENER DRIVE 3633.4461/1972 Kawasaki 81/55 SYSTEM Primary ExaminerJames L. Jones. Jr. [75]lnvemor' Gary Cums Elgm Attorney, Agent, or FirmOlson, Trcxlcr. Woltcrs,[73] Assignce: Illinois Tool Works Inc., Chicago, Bushnell & Fosse, Ltd.

Ill.

22 Filed: Jan. 6, 1975 [57] ABSTRACT A tension-responsive fastener drivesystem is disclosed in which tension arising in a fastener is sensed bya feeler gauge. The gauge applies a retardive force to a 52 US. Cl.8l/52.4 R; 173/12 Sensing Sleeve mounted for motion with the fastener[21] Appl. No.: 538,747

51 Int. c1. B25B 27/00; 825D 23/142 drive Shaft When fastener driveShaft-Sensing Sleeve [58] Field of Search 8l/52.4 R, 52.5; 173/12;motion becomes uhequah or when the Sensing Sleeve 192/150 is angularlydisplaced relative to the drive shaft, a stop mechanism is actuated tohalt further fastener driving [56] References Cited action. Thus. apredetermined tension can be applied UNITED STATES PATENTS to a fastenerwhen the fastener is driven into or secured on a workp1ece. 2,789,5974/l957 La Torre 81/55 3,247,741 4/1966 Batten 81/56 16 Claims, 15Drawing Figures 427, 31 37 '1 L I 1 3 i] ,2" 3; 3553 US Patent Sept.23,1975 Sheet 1 of5 3,906,819

US Patent Sept. 23,1975 Sheet 2 of5 3,906,819

US Patant Sept. 23,1975 Sheet 3 of5 3,906,819

US Patent Sept. 23,1975 Sheet 4 of 5 3,906,819

US Patent Sept. 23,1975 Sheet 5 of 5 3,906,819

TENSION-RESPONSIVE FASTENER DRIVE SYSTEM BACKGROUND OF THE INVENTIONWhen using threaded or like fasteners, it is often desirable to drivethe fastener into a workpiece until a predetermined amount of axialtension arises within the seated fastener. When this can be done,workpieces can be drawn together with known abuttive force, assembliesof precise dimension can be provided, and other desirable technicalconditions can be obtained.

Joints which utilize a spring or resilient member functionallyinterposed between a fastener and a workpiece or between workpiecesinterconnected by a fastener are frequently used to maintain a known orrelatively consistent tension within the fastener. However, such springmembers may relax over a long period of time. In some applications, thespring member permits the joint to undesirably relax or deform undercertain use conditions.

A number of fasteners, fastener drives and fastener systems have beenoffered in which the fastener is driven into a workpiece or is tighteneduntil a predesignated torque force has been applied. However, sinceactual tension produced in a fastener or fastener joint is only roughlyproportional to the fastener drive torque under certain conditions, thesystems are correspondingly unreliable and inaccurate when creation of agiven tension within the fastener is desired.

A tension indicating fastener unit which is relatively accurate inresponding to tension applied to a fastener member is disclosed inco-pending US. Pat. Application No. 437,597, filed Jan. 28, 1974. Ingeneral, this application discloses a fastener having a relativelyenlarged head and a reduced-diameter shank which may be driven into aworkpiece, as by threads provided upon the shank. An axiallycompressible washer such as a conical washer is assembled over the shankbelow the fastener head. A freely rotatable cup-shaped ring gauge ispositioned between the upper surface of the washer and the lower bearingsurface of the fastener head or a nut. As the fastener head is drawntoward the workpiece, the conical washer compresses axially until thering gauge is pinched between the washer and the fastener bearingsurface. At this point, a predetermined tension has been provided in thefastener; this condition is signified by lack of rotatability of thepinched ring gauge.

It is a general object of the present invention to provide a fastenerand fastener drive system which permit driving the fastener toward orinto a workpiece or assembly until a predetermined axial tension isexperienced in the fastener, whereupon fastener tightening action isautomatically halted.

A more specific object of the invention is to provide a fastener drivesystem wherein the driving action is stopped in response to a fastenertension-sensing gauge. In the embodiment disclosed herein, this gaugetakes the form of a ring gauge or-annular feeler gauge surrounding afastener shank and carried between a fastener head and a conical washer.

Another object of the invention is to provide a fastener system having afastener driving device for tightening a fastener, and a sensing sleevedevice for engaging the fastener-tension-responsive gauge. When tensionis sensed, the sensing device operates to halt further fastener drivemotion.

Still another object of the invention is to provide such a system whichcan be used with fastener drive devices which are electrically powered,fluid powered, or which are powered in other manners.

Yet another object of the invention is to provide a fastener drivesystem which is inexpensive in cost, yet reliable and rugged inoperation.

Other objects and advantages of the invention will become apparent uponreading the following detailed description and, upon reference to thedrawings. Throughout the drawings, like reference numerals refer to likeparts.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view inpartial section showing one embodiment of the fastener and the novelfastener drive system as they appear when the drive system beginsdriving the fastener into a workpiece;

FIG. 2 is a fragmentary sectional and elevational view showing in detailthe fastener and related parts of FIG. I in slightly modified version;

FIG. 3 is an elevational view in partial section similar to FIG. I andshowing the drive system as it appears when the fastener has beenrelatively fully driven into a workpiece;

FIG. 4 is an elevational view in partial sections similar in orientationto FIGS. l and 3 showing an alternate embodiment of the fastener drivesystem as it appears when the fastener is beginning to be driven;

FIG. 5 is a sectional partial elevational and sectional view similar toFIG. 4 but showing the drive system as it appears when the fastener isrelatively fully driven;

FIG. 6 is a sectional view taken substantially in the plane of line 66in FIG. 5;

FIG. 7 is a fragmentary sectional view showing yet another embodiment ofthe invention as it appears before the associated fastener has beenfully driven,

FIG. 8 is a sectional view taken substantially in the plane of line 8-8in FIG. 7 showing the drive system as it appears when the fastener hasbeen fully driven;

FIG. 9 is a sectional view taken substantially in the plane of line 88and similar to FIG. 8 but showing the drive system components as theyappear when the fastener has been driven to its final tensile stress;

FIG. 10 is a fragmentary elevational view showing a further embodimentof the invention as it appears before the fastener'has been fullydriven;

FIG. 11 is a fragmentary elevational view similar to FIG. 10 but showingthis embodiment of the invention as it appears when the fastener (notshown) has been fully driven to final tensile strength;

FIG. 12 is a fragmentary sectional view taken substantially in the planeof line 12-12 in FIG. 10;

FIG. 13 is a fragmentary sectional view taken substantially in the planeof line I3l3;

FIG. 14 is a fragmentary elevational view similar to FIG. 10 showing yetanother embodiment of the invention as it appears before the fastenerhas been fully driven; and

FIG. 15 is a fragmentary elevational view similar to FIG. 14 showing theinvention as it appears when the fastener has been fully driven.

DETAILED DESCRIPTION While the invention will be described in connectionwith preferred and alternate embodiments, it will be understood that itis not intended to limit the invention to these embodiments. On thecontrary, it is intended to cover all alternatives, modifications andequivalents as may be included within the spirit and scope of theinvention.

Turning first to FIG. 1-3, there is shown a fastener drive systemembodying the present invention. In general, this system 20 can beconsidered to comprise a drive power source 21, a drive coupler 22 and afastener 23 adapted to be driven at least partly into a workpiece 24.Here, the power drive 20 is electrically operated. However, it iscontemplated, as will be shown hereafter, that this power drive 20 canbe of the fluid power or other known type without departing from thespirit and scope of the invention.

The illustrated fastener 23 includes a bolt-like member having a drivinghead 31 and, formed integrally therewith, a threaded shank portion 32.Surrounding the shank 32 is a conical spring washer 33 which may be ofthe Bellville type. An annular or ring-like feeler gauge 34 terminatesin an annular surface 35 which, as illustrated, is carried between andis adapted to be caught between the upper surface of the Bellvillewasher 33 and a lower bearing surface 36 partly defining the bolt head31. An axially extending gauge cylinder portion 37 is adapted for matingwith portions of the drive coupler 22, as will be more fully explainedhereafter. It will be understood that during such time as the gauge 34is not caught or squeezed between the bolt head 31 and the Bellvillewasher 33, the gauge can be rotated freely about the bolt shank 32, asmay be envisioned from FIG. 1. When, however, the bolt is drivensufficiently into the workpiece 24 to flatten the Bellville washer 33,the annular portion 35 of the ring gauge 34 is, as illustrated in FIG.3, squeezingly trapped between the bolt head 31 and the washer 33;further rotational motion of the ring gauge is frictionally inhibited orfully prevented, except insofar as the bolt head and Bellville washerboth may turn. To inhibit rotation of the Bellville washer, small tangs(not shown) may be formed upon the Bellville washer 33 to engage theworkpiece '24 and render the Bellville washer 33 stationary. Furtherdescription of the bolt, washer, and 7 ring gauge and their co-action iscontained in the above-referenced patent application.

In accordance with the invention, this fastener system 20 drives thefastener 30 until a predetermined tension is experienced or encounteredby the fastener 30. When this tension is appropriately sensed by thefeeler gauge 34 fastener driving action is stopped. To this end, thedrive coupler 22 includes a driving socket 40 connected to an outputshaft 41 of the power source 21. The driving socket 40 is formed withflats or other appropriate surfaces to engage corresponding flats 42formed on the head 31 of the fastener 30. The invention contemplatesthat drive sockets 40 of various sizes may be provided or required tomate with fastener heads 31 of various sizes or shapes. When the powersource 21 is actuated, the drive shaft coupling 40 interconnected withthe fastener 30 drives the fastener 30 into the workpiece 24.

In further accordance with the invention, a torque sensing sleeve means45 concentrically surrounds the coupling drive shaft means 40 and isadapted to grasp the feeler gauge 34. In the embodiment illustrated inFIGS. 1-3, this sensing sleeve 45 includes a first sleeve part 46 and asecond sleeve part 47 formed withmating surfaces such as crown gear-liketeeth 48-and 49 which interengage and cause the first and secondportions 46 and 47 of the coupling 45 to rotate as a single unit absentthe application of retardive torsional force applied to one part only.

To engage the ring feeler gauge 34, the lower extremity of the firstsleeve part 46 is formed with gauge connector fingers 51. When the gauge34 is grasped, the first sleeve part 46 and the gauge 34 rotate togetherwhen the sleeve is rotated. However, when a retardive force is appliedto the gauge 34, rotational motion of the first sleeve part 46 isretarded or halted. As indicated above, such rotationally retardiveforce will be applied through the gauge in response to axially tensileforces incurred by the fastener 30.

To permit the first sleeve part 46 to rotate independently of thesurrounded driving coupling 40, yet to substantially axially co-alignthe part 46 and the coupling 40, an O-ring 53 is provided. This O-ringdiscourages or inhibits relative axial motion between the coupling part46 and the socket 40.

In eontradistinction to the first coupling part 46 which is permittedrotational motion relative to the socket but which is inhibited fromaxial motion relative to the driving socket 40, the second coupling part47 is permitted to undergo axial motion with respect to the drivingsocket 40, but is prohibited from rotational motion with the drivingsocket. To this end, spline teeth 55 interengage corresponding splinegrooves 56 formed on the interior of the second socket part 47. Abiasing member 57 such as a coil spring functionally inserted between asocket collar 58 and a coupling collar 59 normally forces the first andsecond coupling parts 46 and 47 into an axially compressed position suchas that shown in FIG. 1.

Operation of the fastener drive system is relatively automatic. Thedrive socket 40 and drive shaft 41 rotate in a predetermined angulardirection to cause the fastener 30 to be driven into the workpiece 24.As the fastener 30 is driven into the workpiece 24, both the fastener 30and the surrounding ring gauge 34 are rotated at the same angular speed.However, as indicated in FIG. 3, when the ring feeler gauge 34 iscompressed between the fastener head 31 and the Bellville spring 33,rotation of the feeler gauge 34 ceases. Since the second sensing sleevepart 46 is connected thereto, an angularly retardive force is applied tothe second sleeve part 46, and angular rotation of the sleeve part 46 isretarded or ceases.

The drive shaft socket 40, the shaft 41 and sleeve 45 undergosubstantially equal rotational motion in the absence of any angularlyretardive force applied to any part of the sleeve 45. However. thesecond sleeve part 47, splined to the socket 40, continues to undergoangular rotation as the socket 40 is continued to be rotated by thedrive means 21 and the drive shaft.

Under these circumstances, the inclined crown gear teeth surfaces 48 and49 act as cam surfaces to axially separate the second sleeve part 47from the first sleeve part 46, in response to the angular displacementof the still-rotating second sleeve part 47 and interconnected drivesocket 40 relative to the now-stationary first sleeve part 46.

In further accordance with the invention and in response to this axialmotion of the second sleeve part 47, an actuator pin 60 is drivenupwardly bythe second sleeve part collar 59. This pin 60 actuates, inturn, a stop device, which here comprises an electrical switch 61. Sincethe electrical switch 61 is interconnected to the power drive switch 62as indicated in dotted lines in FIG. 1, the stop switch 61 haltsrotation of the drive shaft, so that the fastener 30 is driven into theworkpiece 24 until the predetermined amount of axial tension isexperienced in the fastener, whereupon fastener driving action isautomatically halted.

A slightly modified version of the device is shown in FIG. 2, where afeeler gauge 65 is shown permanently mounted or attached to the lowerextremity of the sensing sleeve 45. By appropriate manipulation, thissensing gauge 65 can be removed from its illustrated position betweenthe fastener head 42 and the Bellville washer 33.

An alternate embodiment of the invention is illustrated in FIGS. 4-6inclusive. Again, in accordance with the invention, a drive shaft device70 is formed at an upper end 71 to accommodate flats 72 or otherconnector surfaces of a power shaft 73. At its lower end, the driveshaft means 70 terminates in flats 75 or other surfaces formed toaccommodate a socket 76. Thus, rotation of the power shaft 73 causesrotation of the driving shaft 70 and the socket 76. The socket 76, inturn, is provided with flats or other surfaces to engage the flats '77formed on a head 78 of the fastener 30.

Concentric with the drive shaft 70 is a sensing sleeve 80 having fingers81 adapted to engage the annular feeler gauge 34. In carrying out theinvention, a nonfrictional interconnector here, a coil spring member 83interconnects the drive shaft 70 and the sensing sleeve 80, and causessubstantially equal rotation of the drive shaft and the sensing sleevein the absence of angularly retardive force applied to the sleeve 80through the gauge-grasping fingers 81.

In accordance with the invention, operation of the driving system ishalted when a predetermined amount of tension has been applied to thefastener 30. Here, a stop device including a circular cam-like member 85having a cam surface 86 is carried on the spring 83 and is adapted forco-action with a ball 87. Radially inward motion of the ball 87 moves anarm 88 pivotally at tached, as by a pin 89, to the drive shaft 73. Asdescribed above, when a predetermined amount of tension has been appliedto the fastener 30, the gauge 34 is squeezed between the Bellvillewasher 33 and the fastener head 78. Rotation of the feeler gauge 34 isthus halted and, in turn, a retardive angular force is applied to thesensing sleeve 80. This retardive force applied to the sensing sleeve 80causes angular displacement of the sleeve 80 with respect to the driveshaft 70. Since the interconnector spring 83 is connected to both thedrive shaft 70 and the sensing sleeve 80, the interconnector spring 83undergoes a wrapping motion as may be envisioned by comparativereference to FIGS. 4 and 5. This wrapping motion angularly displaces thecam member 85 with respect to the drive shaft 70, thereby causing themember 87 to be moved radially inwardly from its position shown in FIG.4 to the position shown in FIG. 5. This cam motion, in turn, moves theball 87 and thus angularly displaces the arm member 88 against thebiasing effect of a small spring member 90 from its running positionshown in FIG. 4 to the stop position shown in FIG. 5.

When the arm 88 is so displaced, a stop pin 91 is permitted to fall fromits armed position shown in FIG. 4 to the actuated position shown inFIG. 5; fall of this pin can be appropriately connected to a pneumaticdriving motor, thereby causing the motor to cease operation and haltrotation of the drive shaft 73. Appropriate bearings such as ballbearings 92 permit smooth angular displacement of the sensing sleeve 80relative to the drive shaft while maintaining the sleeve and shaft inco-axial alignment.

Yet another embodiment of the invention is shown in FIGS. 79 inclusive.There, the driving system takes the general form of an attachmentsecured, as by threads 95, to the muzzle of an electrically energizedpower tool 96 or other device. Again, the fastener driving system can beconsidered to include a drive shaft 70 concentric with and at leastpartially surrounded by a sensing sleeve 80. As in other embodiments,sensing sleeve fingers 81 grasp a feeler gauge 34 functionallyinterposed between the head 78 of a fastener 30 and a Bellville spring33 assembled over the fastener shank. An interconnecting coil spring 83is provided with a modified cam member 98 having a cam surface 99adapted to engage a ball member 100. Here again, the sensing sleeve anddrive shaft 70 undergo relative angular displacement when the fastener30 is tensioned and the feeler gauge 34 is inhibited from furtherrotational motion, and this action causes relative displacement of theinterconnector spring 83. Spring displacement forces the cam member 98attached to the spring to undergo displacement relative to the ballmember 100 mounted upon the drive shaft 70, thereby forcing at least apor tion of the spring radially outwardly away from the drive shaft 70.This action, in turn, forces a cam member 101 also mounted on the springinto engagement with a probe 102 of an electrical switch 103 which canbe conveniently carried upon ajacket 104 surrounding the drive shaft 70and. interconnector spring 83. Engagement of the electrical switch probe102 operates the switch 103, as through appropriate wiring 105, therebyhalting operation of the power tool and halting further rotation of thedrive shaft 70.

Yet another embodiment of the invention is shown in FIGS. 10-13inclusive. Again, in accordance with the invention, a sensing sleeve 80is mounted, as by ball bearings 91, concentrically surrounding a driveshaft device 70. Grasping fingers 81 engage a feeler gauge 34 which isadapted to be. squeezed between a fastener head (not shown) and aBellville washer 33.

As in a previous embodiment, this sensing sleeve 80 can be considered toinclude a first or lower part 108 adapted for rotation with, and forangular displacement relative to the drive shaft 70, but. inhibited fromrelative axial motion. An annular second] section 109 surrounds aportion of the drive shaft 70 and is interconnected thereto by a pinmember 110 to permit axial movement of the second part 109 relative tothe drive shaft 70, but to prohibit relative angular displacement.Interconnecting the first and second parts 108 and 109 of the sensingsleeve 80 is an interconnector spring 112 which engages slots 113 orother appropriate attachment structure on both sleeve parts 108 and 109.By appropriately tensioning or compressing the spring 112 relative axialmotion of the parts 108 and 109 can be caused in response to angulardisplacement of the shaft and sleeve.

In furtherance of the invention, permanent magnets 115-118 inclusive canbe mounted on the first and second sleeve members 108 and 109,respectively. By proper orientation of these magnets, the sleeve parts108 and 109 can be caused to be axially attracted toward one anotherduring initial fastener driving. However, as tension is experienced inthe fastener and sensing sleeve 80 is angularly displaced relative tothe drive shaft means 70, the magnets 115l18 will also be angularlydisplaced from one another. Again, if proper orientation of the magnetsis provided, positive magnetic repulsion will occur, thereby forcingaxial separation of the sleeve parts 108 and 109.

Axial motion of the top sleeve portion 109 whether caused by springbiasing force, magnetic repulsion, or the spring biasing forceovercoming magnetic attraction moves the interconnector pin 110 axiallyupwardly as indicated in FIG. 10. Pin motion, in turn, moves a stop pin120 upwardly to actuate a halt switch and terminate further fastenerdriving motion.

As particularly indicated in FIG. 11, axial separation of the first andsecond sleeve parts 108 and 109 can be further encouraged by providinginclined cam surfaces 122 and 1.23 on the sleeve parts. Here, thiscamming action encourages separation of the sleeve parts until theinterconnector spring 112 can provide sufficient separating force toovercome the magnetically attractive force of the magnets l118.

Yet another embodiment of the invention is shown in FIGS. 14 and 15.Again, the drive device can be attached, as by threads 130 to a powerdriving tool 96. Again, a drive shaft assembly 70 is provided, and is atleast partly surrounded by a sensing sleeve 80 having fingers 81engaging the tension-sensing gauge 34 which is adapted to be trappedbetween the head (not shown) of a fastener 30 and a Bellville spring 33.As in other embodiments, the sensing sleeve device here comprises twoseparate parts 131 and 132 which are axially movable relative to oneanother. A lower or first sensing sleeve member 131 can be mounted tothe housing 104 as by a bearing 135 or by other appropriate structure.So mounted, this lower or first sleeve normally rotates with the driveshaft assembly 70. A second or upper sleeve member 132 is mounted foraxial motion relative to the drive shaft assembly 70, but a pin 136prevents shaft-sleeve angular motion.

As the fastener 30 is tensioned and further angular motion of the lowersleeve member 131 is prohibited, the upper sleeve member 132 isangularly displaced relative to the lower sleeve member 131. ln theembodiment illustrated. an interconnector spring 140 is caused to engagea cam member 141 mounted upon the drive shaft assembly, and drags theupper sleeve member 132 in a downward direction. Such motion of theupper sleeve member relative to the lower sleeve member can be used topull downwardly an axially oriented stop pin 145 to halt fastener drivemotion. Alternatively, an electrical switch 146 can be provided with aprobe 147 adapted to follow a collar 148 formed upon the upper sleevemember 132. Withdrawal of the collar 148 from contact with the switchprobe 147 operates to actuate the stop switch 146; by appropriate wiring150, a drive stop switch (not shown) can be actuated to halt furtherdrive motion and further axial tensioning of the fastener 30.

Embodiments of the invention other than those shown will suggestthemselves to those skilled in the art taught. For example, adifferential gearing may be interposed between the power tool shaft andthe fastener head drive shaft. A sensing sleeve can be driven from onemain differential gear, while the fastener head drive shaft is rotatedat equal angular speed but in the opposite angular direction by theother main differential gear. Ring-mounted pinion gears interconnect thetwo main differential gears; absent retardive force applied to thesensing sleeve, the positions of the pinion gears will remainstationary. When the sensing sleeve motion is retarded, however, thepinion gears and their mounting ring will be caused to be moved. Thisring motion can be used to actuate a drive stop device. Appropriatelyadapted planetary gearing mechanisms and other embodiments of theinvention will also suggest themselves.

The invention is claimed as follows:

1. A fastener drive comprising rotatable drive shaft means adapted fordriving interconnection with a fas tener to drive the fastener into aworkpiece, sensing sleeve means rotatable with the drive shaft andadapted for interconnection with a tension sensing gauge actuated bytension in the fastener, at least a portion of the sensing sleeve beinginhibited from rotation with the drive shaft when tension in thefastener is sensed by the interconnected gauge, and stop means forhalting rotation of the drive shaft when rotation of the sensing sleeveis halted, whereby the fastener is driven into the workpiece until apredetermined amount of tension is experienced in the fastener.

2. A fastener drive according to claim 1 including aetuator means foractuating the stop means in response to angular displacement of thesleeve relative to the drive shaft.

3. A fastener drive according to claim 1 wherein said sleeve includesfirst and second parts axially moved relative to one another in responseto angular displacement of one sleeve part relative to the drive shaftmeans, said stop means being actuated by the sleeve part axial movement.

4. A fastener drive according to claim 3 including magnetic meanscarried on said first and second sleeve parts to magnetically urge saidparts axially toward one another in a predetermined angular relationshiprelative to one another.

5. A fastener drive according to claim 3 including magnetic meanscarried on said first and second sleeve part to encourage axialseparation of said parts in response to the angular displacement of onesleeve part relative to another.

6. A fastener drive according to claim 1 including means for carryingsaid sensing sleeve means in concentric relation with said drive shaftmeans.

7. A fastener drive according to claim 1 including power means fordriving the drive shaft means in a predetermined angular direction tocause the fastener to be driven into the workpiece.

8. A fastener drive comprising a rotatable drive shaft means adapted fordriving interconnection with a fastener to drive the fastener into aworkpiece, sensing sleeve means rotatable with the drive shaft means andadapted for interconnection with a tension sensing gauge actuated bytension in the fastener, nonfrictional interconnector meansinterconnecting the drive shaft means and the sensing sleeve means forcausing substantially equal rotation of the drive shaft means and thesensing sleeve means in the absence of angularly retardive force appliedto the sleeve means and permitting angular displacement of the sleevemeans relative to the drive shaft means in response to an angularlyretardive force applied to the sleeve means, and stop means for haltingrotation of the drive shaft means in response to angular displacementbeyond a predetermined amount of at least a portion of the sensingsleeve means relative to the drive shaft means.

9. A fastener drive according to claim 8 wherein the sensing sleeveincludes gauge connector means adapted to engage said tension sensinggauge with the sleeve, the tension sensing gauge being halted in itsrotation and applying a retardive force to the sensing sleeve means inresponse to tensile forces arising in the fastener.

10. A fastener drive according to claim 8 including actuator means foractuating the stop means in response to angular displacement of thesleeve relative to the drive shaft.

11. A fastener drive according to claim 8 wherein said sensing sleeveincludes first and second sleeve parts axially moved relative to oneanother in response to angular displacement of one sleeve part relativeto the drive shaft means, said stop means being actuated by the sleevepart axial movement.

12. A fastener drive according to claim 8 including means for carryingsaid sensing sleeve means in concentric relation with said drive shaftmeans.

13. A fastener drive according to claim 8 including power means fordriving the drive shaft means in a predetermined angular direction tocause the fastener to be driven into the workpiece.

14. A rotatable drive shaft :means adapted fordriving interconnectionwith a fastener to drive the fastener into a workpiece, sensing sleevemeans rotatable about the drive shaft means and adapted forinterconnection with a tension sensing gauge actuated by tension in thefastener, non-frictional interconnector means interconnecting the driveshaft means and the sensing sleeve means for causing rotation ofsubstantially equal angular speed of the drive shaft means and thesensing sleeve means in the absence of angularly retardive force appliedto the sleeve means and permitting the angular rotation of the sensingsleeve means to be retarded by an angularly retardive force applied tothe sleeve means, and stop means for halting rotation of the drive shaftmeans in response to angular displacement beyond a predetermined amountof at least a portion of the interconnector means relative to the driveshaft means.

15. A fastener drive according to claim 1 wherein the sensing sleevemeans is adapted to rotate in the same angular direction as the drive:shaft rotation.

16. A fastener drive according to claim 1 wherein the sensing sleevemeans is adapted to rotate in the opposite angular direction to thedirection of rotation of the drive shaft.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3.906.819Dated September 23. 1975 lnv fl Gary Martin Curtis It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

C010 8, line 31, after 'second" insert --sleeve- Signed and Scaled thistwentieth D of January 1976 [SEAL] Attest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner of Parentsand Trademarks

1. A fastener drive comprising rotatable drive shaft means adapted fordriving interconnection with a fastener to drive the fastener into aworkpiece, sensing sleeve means rotatable with the drive shaft andadapted for interconnection with a tension sensing gauge actuated bytension in the fastener, at least a portion of the sensing sleeve beinginhibited from rotation with the drive shaft when tension in thefastener is sensed by the interconnected gauge, and stop means forhalting rotation of the drive shaft when rotation of the sensing sleeveis halted, whereby the fastener is driven into the workpiece until apredetermined amount of tension is experienced in the fastener.
 2. Afastener drive according to claim 1 including actuator means foractuating the stop means in response to angular displacement of thesleeve relative to the drive shaft.
 3. A fastener drive according toclaim 1 wherein said sleeve includes first and second parts axiallymoved relative to one another in response to angular displacement of onesleeve part relative to the drive shaft means, said stop means beingactuated by the sleeve part axial movement.
 4. A fastener driveaccording to claim 3 including magnetic means carried on said first andsecond sleeve parts to magnetically urge said parts axially toward oneanother in a predetermined angular relationship relative to one another.5. A fastener drive according to claim 3 including magnetic meanscarried on said first and second sleeve part to encourage axialseparation of said parts in response to the angular displacement of onesleeve part relative to another.
 6. A fastener drive according to claim1 including means for carrying said sensing sleeve means in concentricrelation with said drive shaft means.
 7. A fastener drive according toclaim 1 including power means for driving the drive shaft means in apredetermined angular direction to cause the fastener to be driven intothe workpiece.
 8. A fastener drive comprising a rotatable drive shaftmeans adapted for driving interconnection with a fastener to drive thefastener into a workpiece, sEnsing sleeve means rotatable with the driveshaft means and adapted for interconnection with a tension sensing gaugeactuated by tension in the fastener, non-frictional interconnector meansinterconnecting the drive shaft means and the sensing sleeve means forcausing substantially equal rotation of the drive shaft means and thesensing sleeve means in the absence of angularly retardive force appliedto the sleeve means and permitting angular displacement of the sleevemeans relative to the drive shaft means in response to an angularlyretardive force applied to the sleeve means, and stop means for haltingrotation of the drive shaft means in response to angular displacementbeyond a predetermined amount of at least a portion of the sensingsleeve means relative to the drive shaft means.
 9. A fastener driveaccording to claim 8 wherein the sensing sleeve includes gauge connectormeans adapted to engage said tension sensing gauge with the sleeve, thetension sensing gauge being halted in its rotation and applying aretardive force to the sensing sleeve means in response to tensileforces arising in the fastener.
 10. A fastener drive according to claim8 including actuator means for actuating the stop means in response toangular displacement of the sleeve relative to the drive shaft.
 11. Afastener drive according to claim 8 wherein said sensing sleeve includesfirst and second sleeve parts axially moved relative to one another inresponse to angular displacement of one sleeve part relative to thedrive shaft means, said stop means being actuated by the sleeve partaxial movement.
 12. A fastener drive according to claim 8 includingmeans for carrying said sensing sleeve means in concentric relation withsaid drive shaft means.
 13. A fastener drive according to claim 8including power means for driving the drive shaft means in apredetermined angular direction to cause the fastener to be driven intothe workpiece.
 14. A rotatable drive shaft means adapted for drivinginterconnection with a fastener to drive the fastener into a workpiece,sensing sleeve means rotatable about the drive shaft means and adaptedfor interconnection with a tension sensing gauge actuated by tension inthe fastener, non-frictional interconnector means interconnecting thedrive shaft means and the sensing sleeve means for causing rotation ofsubstantially equal angular speed of the drive shaft means and thesensing sleeve means in the absence of angularly retardive force appliedto the sleeve means and permitting the angular rotation of the sensingsleeve means to be retarded by an angularly retardive force applied tothe sleeve means, and stop means for halting rotation of the drive shaftmeans in response to angular displacement beyond a predetermined amountof at least a portion of the interconnector means relative to the driveshaft means.
 15. A fastener drive according to claim 1 wherein thesensing sleeve means is adapted to rotate in the same angular directionas the drive shaft rotation.
 16. A fastener drive according to claim 1wherein the sensing sleeve means is adapted to rotate in the oppositeangular direction to the direction of rotation of the drive shaft.